System of motor control.



G. B, SGHLEY.

SYSTEM OF MOTOR (10H TROL. APPLICATION PILED'JUIQYB, 1900.

989,063. Patented Apr. 11, 1911.

2 BHEETS-SHEET 1.

G. B. SCHLEY. SYSTEM OF MOTOR CONTROL.

APPLIOATIOH FILED JULY 8,1909.

Patented Apr. 11,1911.

2 SHEETBSHEET 2.

rJ MJ my m M F30 Woo? it ill 1 4 I Hi.

GEGRGE B. SCHLEY, OF IJIILWA'UKEE, WISCDNSEN, ASSIG-N'C'P, IQALLIS-CHALMERS CUMPANY, A CORPORATION OF NET/7 JERSEY.

sY-srnsr or Moron courses.

scones.

Specification of Letters Patent.

Pin-tented Apr. ill, Twill...

Applicatioii filed July 8, 1909. Serial 250. 508,506.

' To all whom it may concern;

lie it known that l, GEORGE E. SoHLnY, grammatically two systemsembodying my a citizen of the United States, residing at Milwaukee inthe county of Milwaukee end State of ll isconsin, have invented certainnew land useful Improvements in Systei'ns of lllotor Control, of whichthetollowing is a full, clear, and exact specification.

My invention relates to motor control stems.

A number of systems have been proposed whereby the moving parts inrolling-mills and in hoisting machinery may be electri eel-1y driven andeconomically and accurately controlled. In the most successful of thesesystems a special generator has been used for supplying the armature ofthe mo tor which does the work, and this motor has been controlled byvarying and reversing the field of the generator and sometimes byvarying the field of the motor. The field circuits of both the motor andthe special generator have usually been supplied from some auxiliarysource of current. ln order to prevent the voltage of the specialgenerator of such a system rom being varied so rapidly as to causedangerously large aransture currents, it has been proposed to providemeans for stopping the progression of the main motor controller in casethe cur; rent in the motor armature circuit exceeds a predeterminedvalue. These proposed schemes for protecting against dangerously largecurrents, While operating satisfactorily to prevent current-increasingprogression of the main controller while the armature current exceedssuch predetermined value, also at the some time incidentally preventcurrent-decreasing movement thereof. Under some circumstancescurrent-decreasing movement of the controller is eminently desirable,

ven though current-increasing movement is prevented.

It is the object of this invention to prevent current-increasingoperation ol' a main motor controller, particularly in such a system asabove described, in case the motor armature current exceeds apredetermined value, and yetto allow currcnt-decreusing operation ofsaid controller at all times.

The various novel features of my invention will be apparent from thedescription and drawings, and will be particularly pointed out in theclaims.

The two figures of the drawing show clisinvention. In the arrangementshown in Figure 1, an electric motor A drives a generator B.

being preferably directly connected thereto;

and on the common shaft of the motor and generator is e heavy fly-wheelC. The arrow ture oi the generator ll is electrically con nected to thearmature of at working motor l), which may be used to drive any desiredmachinery.

The motor-A is illustrated as being of the three-phase induction type,though obviously other forms of motors could be used instead. In therotor circuit of this motor is a starting resistance 1 adjustable bymenus of a short-circuitgng bar and a regulating resistance 3 arrangedto be out in and out by solenoid switch 4. in turn responsive to thecurrent strength in the primary circuit of the motor as throughseries-tronsforincr 5. Other means for varying the speed of the motor Amay be used if de sired.

The field windings b of the generator and (Z of the Working motor aresupplied from any suitable direct current source through a, switch 6,the same source also supplying the various controlling circuits. in thesin cult of the field. coils b is e reversing switch 5 '7, which isbiased toward its middle or open position, but which may be moved to itsextreme positions by solenoids 8 and 9 respectively to complete thegenerator field circuit in the desired direction. of resistance switches11 to 15 are provided, the'switches 12 to 15 nori'nslly Sl'lOIt-Clicuitin resistance sections 17 to 20 respectively in the circuit of themotor field winch ing (Z. The switches ii to 15 may be raised 95versiblc coil 34 ll; the circuit including he armotures l3 and. l) sntlpolarizing coil is number th is swih 35 comumticd in any desired manner.as in shunt. across the line supplied through the switch (3. Either orboth ot the coils 2H; and 3:3 may he adjustable. a, rhcostat 3 t bcinslmwn for adjusting the coil ll. 'lf'he armature ot the motor 132 isnoruiallv shortcircuited by a. switch 30, but this switch is:mtomaiicall) opened by one or the other when either 1; energglzed.

of two solenoids it? and of the field coils ot the mole is Zed, theswitch 113 is closed to shortllll toe armature ol. the pilot motor uponitself to brake it.

The operation of the stcm is as follows;--lhe. primary circuit of motorA. is closed and the motor started by moving the bar 3 to cut out theistance 1. The switch 4- 'is held open by its solenoid at this timebecause of the heavy current required for starting the .rnotor. l tdesired, other means mav housed to insure the open condition of I 1during starting. A t ter the motor hasv on: ad sulhcieut speed and thestarting resistanc l been cut. out. the solenoi-zfl switch t allowed toclose to out. resist:-

Thus when neither of these held windim one i ancebecause of the decreasein the primarv current oil motor A. The lly-wheel C and the generatorarmature B are also started with the motor A, and the lly-wheel storesmechanicalv energy by its rotation. Durir this start ing; the arm 40 ofthe master .;oatr .)llcr ll. a nd the arm 31 of the intermedia tocontroller ltl are pre'l'eraldy in their vertical or ojtl position Theswitch (3 now hen 5 closed, the motor lield d is at its stronge t, forit; has none of the resistance sectioiis 17 to 20 in circuit. with it-.'The generator lield 1/) is dei nergixed because the icversing switch 7is in its middle or open position.

The arm 40 is now moved from the con tact 4-3 to one of the othercontacts to either side thereof in the proper direction to give themotor I) the desired direction of iota. tion. There may be any number ofcontacts cooperating with the arm 'll). the numher of contact SCQjiHQHtS51 to (50 suitably corresponding. Assume that: this arm is moved intoei'igagement with contact 4]. This closes the circuit through the arm4-0, contact l'l. contact segment 5?, arm 31, contact segment. 51, fieldcoil ll}, solenoid. 37, switch 4-9, and armature 32 ot the pilot motor.The solenoid 37 in'nnediately opens the switch 36, and the motor rotates to move the arm 31 in. the proper direction, here coenter-clockwise.As the arm 31. leaves the vertical it, first engages the contact, button(3] to complete the circuit oi the solenoid S to close the reversin;switch 7 in. the proper direction, say to the left. This completes thecircuit of the field coil Z through the resistance sections 26 to 29,and causes said generator to grin rate a small electromotive force,which, he-

as do the switches 11 and 15.

jug impressed on the armature .l), may cause the working motor to startand rotate at a. l w speed.

As the motor continues to mor the arm 31 counter-trio (wise, said armleaves button (it and cup: es uitton (32 to connect the solenoid it inseries with the solenoid o to close the switch ll. This sl'iort-circuiisthe res-i" ice section .{li to lll('l:i| the hold strength andthcrcli'ore the clcctromoiive l'orce of the generator it, therebyincreasingthe speed ot the working motor l). it, may also he arranged tocut a section of resistance into circuit with the .motor licl l winihing (Z to decrease the lield strength of the working motor to aid in theincreasing of its speed, though prefer; bly the motor lield strengthnot. varied until later. As the arm 23.! continues to be moved by themot r 32 it suc .ssivcly connects in circuit the solenoids -2, 23, 91!,and 33 to raise the switches 12. 13, .-l, and L3, thus graduallyincreasing the field strength ol. the generator l3 and decreasing thelield strength ol the workingmotor l). both of which actions tend toincrease the speed of said motor. When the last. switch 15 has beenraised. the pilot motor stops because the arm 3 has left the segment 52.There may be any nun: her oil. the solenoids it to .2? and acorrcspending number of switches ll to 15. 'lhc llldlVltlllal switchesof this group may control resistance sections in both the generator andmotor field circuits, as do the switches 12. 13. and 14:, or in one onlyof said circuits,

I as desired.

As the solenoids 2.1 to 25 are succe. 'ivcly connected. in series withthe solenoid S, the resistance of the circuit: including said solonoidsis gradually increased, thus slighthJ diminishing the current in saidcircuit. In

rder to avoid a too great variation in the current on this account, aresistance 4.8 is rn'eterahly connected in the circuit including thesolenoids. The value of this resistance relative to the rcsist.an ':c ofthe solenoids may be such as to make the variatiol'i o't. current due tothe cutting in fill the solenoids 21 to 25 as small desired.

It the arm 40 had been moved only from button 4-3 to button; 4-2,however, the motor 32 would not have continued to, drive the arm 31 tocause the operation ot'all of the. switches 11. to 15 inclusive..lnstead. when the arm 3']. has reached contact o li'as illus trated,thereby having caused the closing of the switches It and l2. it willalso have left; the contact segment 53. thereby breakingthe circuit; ofthe pilot. motor It the load heavy the working motor requires, morepower l'or its starting than the motor it. can furnish. The current rising i the primary o'l translprmcr .3 h rea son of this heavy load. theswitch -;topener husins.,.rt;ingresi c Sinthcr-olor ill) circuit ofmotor A. This increases the slip of motor A and permits said motor toslow down, thus allowing the flywheel O to give up some of themechanical energy it has stored, which energy helps the motor A to drivethe generator B to supply electrical energy at the rate demanded by themotor 1) to drive its load.

When it is desired to slow down or stop the motor D the arm 40 is movedtoward or to the contact 43. This causes the motor 32 to move the arm 31back toward the vertical, or in a clock-wise direction, allowing some orall of the switches 15, l4, 13, 12, 11, and 7 to return to their normalpositions in the order named to increase the field strength of the motorD, to decrease the electromotive force of the generator B, and finallyto interrupt the circuit of the generator field winding 6. While this istaking place, the motor D acts temporarily as a generator to supply thearmature of the machine B, the latter serving as a motor to help restoreenergy to the fly-wheel C. There is powerful dynamic braking effect uponthe working motor due to its acting as a generator. W'hen the motor 32drives the arm 31 in a clockwise direction, the field coil 47 isenergized instead of the field coil 46, the motor circuit beingcompleted through the proper contacts of the master controller H and ofthe inter mediate controller E, the field coil 47, the solenoid 38, theswitch 50, and the armature of the motor 32. The solenoid 38 holds theswitch 36 open While this circuit is maintained.

lVhen the load on the generator B diminishes below the value at whichthe switch 4 opened, either because the motor D has ceased acceleratingor because said motor is being slowed down and is running as a generatorto drive the machine B as a motor, the'diminished current in the primaryof the transformer 5 causes the solenoid switch 4 to close. Thisincreases the speed of the motor A s0 that the latter may supply or helpsupply energy to the. fly-wheel C. The fly-wheel thus stores'up anyexcess of energy supplied when the rate of such supply exceeds the rateat which energy is demanded by the working motor, and gives up saidstored energy whenever the rate of energy demanded is greater than therate of energy su plied. W hen the arm 40 is moved in the ot erdirection' from the vertical to engage the contacts 44 or 45, the arm 31is caused to move similarly in a clockwise direction, energizing thesolenoid 9 to close the reversing switch 7 to the right and causing asmany of the switches 11 to 15 to be raised as desired. The cycledescribed above is repeated save that the direction of rotation of theWorking motor D is reversed.

In case the movement of the arm 31 should be so rapid, either toward orfrom the vertical, that it causes the current in the arnniture circuitof the machines 13 and l) to rise leyond the predetermined value forwhich the polarized relay- 33 is set, the movable member oi? saidsolenoid is moved to open the switch 4) or 30 as the case may be, thusdisconnecting the motor 32 from the source of supply. Only that one ofthe switches 45) and 50 through which the current for the motor 32 isbeing supplied, is opened. The opening of the switch 49 or 50delinergizes the solenoid 37 or 38 and thus allows the switch 36 toclose to short-circuit the armature of the motor 32 upon itself. Theinterruption of the pilot motor circuit and the short-circuiting of thepilot v motor armature upon itself causes the armature to stopimmediately wherever it may be. In some instances the short-circuitingswitch 36 and its solenoids may be omitted. The circuit of the pilotmotor for movement in the same direction cannot be closed again untilthe currentin the armature circuit of the motor I) has fallen below thepredetcrmined value for which the polarized relay is set, when saidpolarized relay allows the switch 49 or 50 to close again. However, thecircuit of the pilot motor 32 may be closed for movement in the otherdirection by a proper movement of the arm 40 of the master controller H.Thus the polarized relay 33 and the switches 49 and 50 prevent theoperation of the main controller to increase the current in the armaturecircuit of the machines B and D if such current exceeds a predeterminedvalue, while at all times allowing the operation of such controller todecrease such current.

When it is desired to vary the speed of the motoig D from any value inone'direction to any in the other direction the arm 40 is moved-from thecontact with which it was in engagement, say 42, to a contact on theother side of 43, say 45. This causes arm 31 to move to its extremeclockwise position, so that the switches 12, 11, and 7 are returned totheir normal position in the order named. the switch 7 then movedt'o theright and the switches 11 to 15 raised in the order named. By thearrangeinent'of contact segments 51 to 60 shown, the motor 32 will movethe arm 31. to a position corresponding to any circuit-closing positionof the arm 40, whatever the position of the arm 31. may previously havebeen. movement of the arm 31 may be stopped at any point by so movingthe arm 40 that it is not in engagement with any of the contacts 41 to45 inclusive. If in this operation of the controller, or in any otheroperation of the controller, the current in the arn'iature circuit ofthe machines B and D exceeds in either direction the predeterminedmaximum'for which the polarized relay 33 is set, such relay immediatelyoperates to open the scopes v .i ii svitch if; or o0 to stop the furtherproll nioiusiie, by means oiv \ihun tiuoi, crcssion of the into;switches are caused to close in Sl'LCPQSllOD.

"iciliute controller und oi the switches controlled icrcby. ell'ectirclypic cnls the current in lllli. circuit l'roni bccoiuin unduly hi utsince only one of the .c-hes h) an 50 is openeih it is pos ible b propern'rinipulzition oi, the llllSi'Oi con oller ii to cause the interlochatecontroller E und the si'iitciics controlled thereby to operate todecrease the current; in the urinuiurc circuit of the nuiis the chinesand D. "iih of the direction in which is retailing and rin urd suchinuchinc is-rcceiring cur: tor or suppl ing current driven by thenion'ieniuin Fig. 2 shows my invention as 10in of the some g'cnerul i uCllll tl'tll'li type of (it/1,. i'ol up :is be" c. the miniature ot. tl) is connected to that of the and the field windin Z) erutor and motorrespcci w hither ml: :is 11 mo- :is generator of the moving applied to uriturc hut with purutus. Here, he innin motor and (Z of the genusethrough the SWltt 1 i=2 7 winding (Z ot the motor in: ji'istiible infilltl'lglll, either by the main. control zippurzitus or by means of a.rhco; ii The field circuit the gencrutor is connected to the line forone oirection of current by elec'tro-u1ugneticull' operuted switches Pand I, and for the other diroclion or or rent by similar switches l andl. The field resistance, made up of sections R to RC winding 7) oi. thegenerator tliijiu 'li the field iy also he zidfield circuit ofshort-circuitcd section by section by electromagnetically oper dswitches 71 to 77 in elusive. The in i tcr swit h K controls theonerzition oi the several, switches 1 1, Qt, g rind 71. to F onerulincurrent for t iese iii) l tuhl source of current in this instance ihcthe for holding closed those oil? the switches 71 to which have been cied In the thirc on Qtflll'llilll l to generutor B,

ii'cly ure supplied 1mm :2. separate soulc" of current. in this} i i Thecoi'itrol} :ip nuutus controls the I rcnc'th oi the lield 1 is normallyconnected in the i the generator 8, but inuy be switches. This causesniorcd to is such the t FlDPl, through such tinge I ie wire 80 the lowerinterlocking switch 7; on the switch if. the actuating coils of theswitches .l" and I to tltreturn wire 81, common to the solenoids oil.all the electrounugnctic the si'i'itches 1 end P to close. The switch Iin (ilOFillg opens its lOWOlHlOSt interlocking switch 72, closes themiddle three interlocking switches 7 p5 und p and moves its uppern'iostinter:

locking switch 7.) from lower to upper position. The closing ol theswitches i und .i completes the circuit of the field windiu 7/ throughall the sections lit to i ]Ht]]t'C:-l to g; nerut'c. This sup ilic. theurniuiure ot the motor l) with current, and nuiy sturt such motor torotating. This condition (niniinues while t-ic inzister controllerrciuziius in us .t'irst orwurd position it is unwed to ":CC'tHlt :torwin order in inircuse t c'enerutor l3.

51c ie rotor :uid the generator 5 coinl h the .uizisler coniroll the thiit rhich u circuit completed from the source through the crs Z1 and Zrto the wire 82, the interh'ickinoswitch the coil of the notchiug relay0, the switch 101, and through the two contucts of the note-hing relay 0to the wires 8-3 and 84; respectively.

two wires zireconnected,through VfUlous intcrlocli'ing cinitucts on theswitches 71. to T7 to the actuating coils of the switches 71, 73, 75,7?, and 72, 741, 76 respectively. With the COTlU'Ollti' K in this thirdforward position, the switches 71 to 77 c osc 'succes sircly under thecontrol oi? the notching rchq" U Hill the switch 101. desired, a (lushnot 0 or sin'iihir dcjvicc may be provided for retuidi'iothe closingmotion of the notchi 'ig reluy t), or such relay n'iay be ni'iitedaltogether.

Th arrzu'igeincntof the interlocking switches on the resistanceswitcl'ics 71 to 7? each of the latter switches by opening switch .9 andclosing switch Z, shifts its uctuutii'ig coil from connection with oneof the actuating wires 83 or 84- to connectorwurd position, in

tion, through a switch. 11 on the next resist res stunce switches 71 to76, when closed by ll 0 closing of its associated resistance res tocomplete the circuit of the actuating coil of the next resistance switchto the right. Oneach or the resistance switches T2 to T7 there areinterlocking switches w and it, which upon the closing of theirassociated resistance switches shift the actuating; coil oil thepreceding resistance switch (to the left) from connection with the firstmaintaining wire 95 to connection with the second maintaining wire 87.The wire 87 is connected directly to the positive side of the source,independently or the master switch K. With this arrange ment, in orderfor any switch 71 to T6 to open, it is neces ary that the next switch tothe right he first opened. The resistance switch 71 is provided with aninterloclr ,1

switch which, when such resistance switch is closed, also closed tocomplete a maintaining circuit for the switches P and P or P and 1. Thismaintaining circuit extends from the switch 0' through the wire 87,interlocking switch it. wire 89, and interloclring switch yr to the wire80, which is connected through the switch p to the actuating coils ofswitches P and P Thus the switches P and P atter having once beenclosed, are held closed independently of the position of the masterswitch, as long as the switch 71 remains closed. Since this switch 7?cannot open until all the switches 72 to 7'? have opened, the switches Pand P cannot open while any of the resistances 1 it to R is cut out ofcircuit.

The circuits for tilIG TGVQI'SG positions of the master switch Kcorrespond closely to those for the forward positions thereof, thefingers H, 0 and in taking the place of the fingers A1 and/c", and theswitches P and l?" and. the interlocking switches operated by the switchP taking the place of the switches P and P and the interlocking switchesoperated hythe switch I.

As long as the master switch K is held in its third forward position,the resistance controlling" switches 71 to 77 will close in successionunder the control of the notching relay O and the switch 101. and willgradually increase the current in the field circuit of the generator B,-thus increasing the This increases the voltage applied to the armatureof the motor D and therefore the speed of such motor. if during; thisoperation the master switch K be turned to its second forward position.the circuitstarting' from the finger la is interrupted. and thesuccessive closing of the switches 71 to '77 ceases. However. all of theswitches 71 to 77 which have hccn closed will he held closed. the lastto close being maintained closed by current sup plied thronsz'h themaster switch and the first maintaining wire and the others which havehorn closed hciug' energized from the second maintaining wire 47, Thethird position oi the master switch is thus anacceleratingr position.and the second a maintaining position.

it with the master switch K in the third forward position the current inthe armature circuit oi the machines P) and D excct-ds a predet rmine:lvalue. the snitch 101 opened to stop further closing of the switches 71to T7 and further increase in the voltage of the generator B. Thisopening of the switch 101 is obtained by the polariycd relay 102. one ofthe coils 103 of which (.Olillttftttl in series with the armature B andD. whilethe other coil 10 i connected across the circuit supplied. bythe switchiti through the interlocking switches 7) in its upper positionand 7) in its lower position. For the reverse rotation of the motor Dthe switch 79 is up and switch 77 down. Either or both of the coils 103,and 104: may be adjustahlcfa rhcostat 105 for adjusting the strength ofthe coil 10% being shown. If desired, other means may he provided foradjusting the polarized. relay 102. By means of this polarized relay.the switch 101 is opened whenever during the progressive closing of theswitches 71 to 77 the current. in the armaturecircuit of the machines Band D exceeds the predetermined value for which the polarized relay isset.

The polarized relay 102 controls a second switch 106. The switch 106 isnormally open, but when closed connects the maintaining wires 85, 87.and 89; that is, it connects the maintaining wires and 89 directly tothe source. independently of the master switch K. The switch 106 isclosed whenever the machine B is acting as a motor and the current inthe armature circuit of the machines B and D exceeds the predeterminedvalue for which the relay 102 is set.

If the master switch K is in its second and third forward position andit is desired to slow down the motor D, to stop it altogether, toreverse it at slow speed, or to reverse it. at higher speed, the mastercontroller is moved backward to the first forward position. to the oilposition. to the first o 'sccond reverse position, or to the thirdreverse position respectively. lt will he assumed that the mastercontroller is moved from the second or third forward position to thethird reverse posi tion, as the operations resulting from this willinclude all those which would result from any of the other n'ioremcntsof tlic u'iaster controller. lt will also he assumed that the motor D isoperating in the forward direction with at least some of the resistanccs R. to n cut out.

The H'IUYPIHPHt oi? the master controller K backward from its secondforward position. regardless oi how far it goes, n'oaks the connectionof the maii'itaining wire to the source through the master crmtroller.lhis detinergizcs the ope 'atinp; coil oi the last of esocee theresistance switches H to T7 inclusive which has been closed, this beingthe only resi tance switch whose i'ictuatingcoil is do pendent uponcurrent from the maintaining wire 85. This switch. say switch 75. atonce opens, transterring the actuating coil ot the next switchto theleft, the switch Tl from the maintaining wire 87' to the maintainingwireand causes such actuatingcoil to he ileener izetl. Dash-pols or similar(teviccs n'iay, 1' desired. he provided for retarding the dropping ofthe switches 71 to T? or of the various switches 0: anti a). Theactuatingcoils of the switches 73. 72, and 71 will he cleener zizetlsuccessively in a similar manner. This diminishes the voltage of thegenerator B, and may diminish it sutlieiently to cause it to act as amotor receiving current from the machine D, clriveu as a generator byits own momentum and the m0 mentum of the apparatus driven by it. ll thevoltage of the machine I) exceeds that of he machine B sutliciently toraise the curent in the armature circuit of the two mah ines ahove thepi'eileterminetl maximum tor which the polarizetl "clay it)? is set. suh to iy *ii'mnctliately closes the switch 'ttht, thus connecting themaintaining wire 85 to the. maintaining wire 8'! and preventing further(leenergizatiou of the actuatin roils of the switches 71 to 77. Theswitch 106 will remain closed, preventing further opening of theswitches it to 7?, until the current in the armature circuit of themachines B and tlrops below such predetermined maximum, but will open toallow such c energization to continue soon as such current falls belowsuch. maxinnun. But With the switch 106 closed, even with the aru'laturecurrent above such. maximum, the operator may. by moving the mastercontroller K to the tliltll forwartl position, cause the switches 71 toi"? to close in proper succc on to increase vol of E and thus d minishthe curin the era iture eircu'; of the machines h of the generator llsutlieiently iJtElt w that; of the cause an e t'io u as the terra e it vof cur- .it in the armature circuit of said mach nes.

1. the switches T to T7 open in or-rler. it such current is atOI'iOltfl'lt to cause the ole of ii tOtl. the s vitches l and t thenopen, the ma intainine circuit of the actuatii'igc ils of these sw t hesheiuo' iiitij-rruptctl by the opei'iin y o'l i'e iutei'lo on switch inon the resistance switch '71. But; it upon the opeaiiu o! llutch '71 thecurrent in the at nature ci:'

1' "f 'nli ;:iently to cause. the polar ixetl relay it to close theswitch ltlt'i. 1h

will not he (lisconuecteil from the source by the oi iening oi" the rulehir switch a; iitltt such switches i and i will not: open until the haclbeen moved to the th rd (or any} 'erse position the opening of theswitches amt l completes the 'ircuit ot the actu- :ltitllg coils of theswitches P antl it" throug'l the contact lingers Zr and W the mastercontroller anti the intcrloclcin; switch 7')", thus reversing thedirection ol current in the t'itfltl coil 71 aml therefore the voltage()l the machine .8. The opening of the switch 1 amt the closing of theswitch l acting through the switches p' aml p". reveis the (llt0( ion ofcurrent in the poarizing coil ltht ot the polarized relay l 02.

After the switches P and l are eloser'li the switches 7.1 to 77 areclosed successively to raise the voltage of the gene *ator B in itsreverse direction. it (luring this opera tion. the current in thearmature circuit of the llltit'illtlt-fi l) aml l rises ahovc thepreileie polarized rc- :novcmei'it: will cause proper Opt" a'tl snitchcs'7 to 77. aml. it do. i. ot switches l to l to diminish the current inFitch armature ci cuit. in t) the polai'iz tl relay lOi amt the swtit-hes lilt amt 106 prevent o )eration of the variousswitche it to T7ami l to P to increase the current in the armature circuit oi he machineanil l) wheneve much current cxceeils a met tcrmincil vaiue. thiscurrent may he either i'li 'tion. am'l mav he (hi (it c l5 :ltitl oi theoth r. lion of these sw' che \vili i whenever such current ext-coils itwhich the nolarizei'l relav'l is while the operat on ot th se .liventett tor current increasing o 'ie i'anou thereof. it is lllltHY-itlat all time For ("urn-tit decreasing; operation thereot. tor the switchltil is never hen at the same time the witch tilt; i-Zoseti.

-' 'ousmoililicatit cements herein in c to an )ltiitz'r ot either of themach" he opera- 1 any point.

to value for Isis ai'ran ml all such which com he ill2l tt' in il:

amt m aim to cover in or. means for Saul relay opens the switch Citvarying and reversing the voltage thereof, a motor connected to saidgenerator, and means responsive to the current in the motor circuit forpreventing said controlling means from varying the voltage of said ge ne 'ator to increase the current in said circuit beyond a predetermined*alue while always allowing it to vary such voltage to diminish thecurrent in said circuit.

2. In combination, a generator, a motor connected to said generator,means for varying the voltage of said generator, and means responsive tothe current in the motor circuit for preventing the voltage of thegenerator from being varied to increase the. current in themotor circuitbeyond a prede termined value whileat all times allowing the voltage ofthe generator to be varied to reduce such current. v

In combination, a generator having a separately excited field circuit, afield resistance, switches-for, connecting said field circuit to' asource ofcurrent for either direc tion of current How and for regulatingthe amount of said resistancein said circuit, amaster switch controllingthe operation ot' said switches, a motor connected to said generator,and means responsive to the current in the motor circuit for preventingsaid switches from responding to movements of the master switch duringretardation, reversal, or acceleration of the motor to increase thecurrent in the motor circuit beyond a predetermined value While allowingsuch response at any time to lessen the curre'nt in.

the motor circuit.

4. In combination, a generator having a separately excited fieldcircuit, a field re sist'ance, switches for connecting said fieldcircuit to asourc'e or current and for regulating the amount of saidresistance in said circuit, a motor connected to said generator,

and means responsive to the current in the motor-circuit and cooperatingwith said switches for preventing the operation of said switches toincrease the current in the motor circuitbeyond a predetermined valuewhile allowing the operation of the switches at any time to decreasesuch current.

.snln combination, a generator having a separately excited fieldcircuit, a field resistance, switches ,for connecting said field circuitso' a source of current for either direction of current fi )V and forregulating the amount of said resistance in said circuit, a motorconnected to said" generator, and means responsive to the current in themotor circuit and cooperating with said switches for preventing suchresistance from being inserted, the connection of" the field circuitwith the source reversed, or the resistance cut out it such action wouldincrease the current in the motor circuit beyond a predetermined value,whileallowing such action if it would decrease said current.

current in the motor circuit.

6. In combination, a generator having a separately excited fieldcircuit, a field -resist-a nce, electrically. controlled switches forconnecting said field circuit to a source of current through saidresistance and for reg-- ulating the amount of said resistance in thefield circuit, a master switch for controlling the operation of saidswitches, amotor conncct-ed to said generator, and means responsive tothe current in the motor circuit for preventing said switches fromcutting "out or re-inserting such resistance only if such cutting orre-ii'is'ertion would increase the current in the motor circuit beyond apredetermined value.

7. In combination, a generator having a separately excited fieldcircuit, a field resistance, electrically controlled switches forconnecting said field circuit to a source of f current through saidresistance for either direction of current How and for regulating theamount ot. said resistance inthe field circuit, a master switch forcontrolling the operation of said switches, a motor {connected to saidgenerator, and means responsive to the current in the motor circuitforstopping said switches from responding to a movement of the masterswitch from any position to another whenever such "resptinse wouldincrease the current of the motor c1r cuit beyond a predetermined valuewhile allowing such swltches to respond to a movement ot the masterswitch from any pos tion to another whenever such response would.

diminish the current in the motor circuit,

8. In combination, a generator, means for varying the voltage thereof,a'motor connected to said generator, and means responsive to the currentin-the motor circuit 'for preventing an increase in the voltage of saidgenerator sufficiently to increase the current in the motor circuitabove a predetermined value while at all times allowing a decrease ofsuch'voltage to diminish the current in the 7 motor circuit.

9. In combination, a generator, means ,for

varying the voltage thereof, a motor c(in nected to said generator, andmeans responsive to the current in'the motor circuit for preventing thevoltage of the generator from being decreased sufiiciently to raise thecurrent in the motor circuit above a predetermined'value while at alltimes allowing such voltage to be increased to diminish the ibo allowingsuch reversal whenever "it would diminish such current.

11. In combination, ascparately excited.

menus rev-30nfor we of {he 'voltug of said In. kllv 2110101 circuu valueWhile ulluwiu olt; 'lio be inmsuusul \vhvncver such IHCXQQSQ \vuuld d1-mums-l1 such (tumult.

l0 lm lcm'mu ccl at any limo when such (l0- mmw. wouldilTHDISh hecuri'vul 1n llm nmi'or vu'cml'.

(he controller to 111 'e Wlnmm'm' ll; m flu! n'mlzoi mil flan;

I- I I Mummy vx-ulm -.myi1'1g flu potmuuu miure. ilwl'u-iwl', 111ml.said conlzmllcl' from a .m urc xl upon he whenwer such all} the currentin the 1m above a prcdcterm111w! said controller l0 in reuse suchvolf'nge fi/llOllCu'Gl' such in would diminish the ("lll'l'lllli in themoi-01' 7 circuit; 7 4

l8. l1: combinatimu u mOlLOI', 2L source of Hlji Ply which sometimessupplies current i0 suclz motor and smnctirms; receives current1'l101'Q:l'1'( u confrnllel' 'fm' Such motor, and. 11183118 mr 1 'entinglhe (moi-M 1011 0'? such coniruller to 11101192150 t w current in them0- lm' :urummre beyond a L'QKlOlZBImlIIQCl value lul at all 611165nllmvmg H10 controller to rjlecrease the current in i'lle motorzu'mu'l'm'e circuit,

. url) current.

:1 uonhmller f varying "';1C';il n, u, sepz Ll 'UICIfQfO; 21 12,1 012110 (10, :mxl. 110m: out of Such cut would i' mural on? be; value,Wl'illQ EL] Owing; Eu we? it WLd-uld a l ul'lim" out ml;

u comm] nected thereto, a field resistance for said.

generator, means for varying said resistance, and means for preventingthe insertionot such resistance whenever such insertion would increasethe current in the motor armature circuit beyond a predetermined value,while allowing the resistance to be cut out whenever such cutting outwould diminish such current.

24. In combination, a separately excited generator, a separately excitedmotor connectedthereto, a field resistance tor said generator. means forconnecting the generator field to a source of current for eitherdirection of current iiow and for cutting the resistance into and outoft-circuit, and means responsive to the current in the motor circuitfor preventing the cutting" in or out of such resistance or the reversalof the connection between the generator field and the source or supplywhen such cutting in or outer reversal would increase the current in themotor armature beyond a. predetermined value, while allowing suchcutting in or out or reversal whenever it would diminish such current.

25. In combination, a generator having or separately excited fieldcircuit, a field resistance, switches for regulating the amount of saidresistance in said circuit, a master switch for controlling theoperation of said switches, a motor connected to said generator, andmeans responsive to the current in I the motor circuit for regulatingthe rate at which said switches respond to movements of said masterswitch to increase such current, while leaving said switches free at alltimes to respond to movements of said master switch to decrease suchcurrent.

26. In combination, a generator having a separately excited fieldcircuit, a field re sistance, electrically controlled switches forregulating the amount of said resistance in the field circuit, amaster-switch for controlling the operations of said switches, a motorconnected to said generator, and means responsive to the current in themotor circuit for regulating the rate at which said switches cut outsaid resistance when the master-switch is moved to increase the motorspeed and the rate at which said switches reinsert said resistance whenthe master switch is moved to decrease the motor speed provided suchcutting out or re-' insertion tends to increase such current, whileleaving the switches free at all times to respond to movements of saidmaster switch to decrease sucn current.

27. In combination, a generator having a separately excited fieldcircuit, a field re sistance, electrically controlled switches forregulating the amount of said resistance in the field circuit, masterswitch for controlling the operation of said switches, a

motor connected to said generator, and.

e: his?) means responsive to the current in the motor circuit forregulating the rate'at which said switches respond to a movement of themaster switch from any position to another when such response wouldincrease such current, while leaving said switches free at all times tomake such response when the latter would decrease such current.

28. In combination, a generator, a motor supplied thereby, apower-operated controller for controlling the electromotive force ofsaid generator, a master controller for controlling the operation ofsaid poweroperated c'onti'oll .r, and means res mnsivc to the current inthe motor circuit for controlling the rate at which the poweroper atedcontroller responds to movements of the master controller to increasesuch current, while leaving it free at all times to make such responseto decrease such current.

29. In combination, a geneiwtor, motor supplicdthcreby. av plurality ofpower-operatcd switches for controlling the electro motive force of saidgenerator, a master controller for controlling the operation or saidpower-operatcd switches, and means responsive to the current in themotor circuit for regulating the rate at which said switches respond tomovements of the mas ter controller to increase such current, whileleaving said switches free at all times to make such response todecrease such current.

30. In combination, a generator, a motor, the armatures of the generatorand motor being connected in series and the generator 7 having aseparately excited field, power-- operated controller for controllingthe field strength of the generator, a master controlhnr for controllingthe operation of said poweroperated controller. and means respons to thecurrent in the circuit includinsr the armatnres of the generator and themotor for controlling the rate at which said power operated controllerresponds to movements of the master controller to increase such current,while leaving: said power-opcraied controller free at all times to maltesuch response to decrease such current.

31. In combination, a motor, a ecnuaior, the armatures of the generatorand the mm tor being connected in a. series circuit and the generatorhaving a separately excited field, a plurality of power-operatedswitches for controlling the field strenoih of sa d generator, a mastercontroller for control ling: the operation of said switches, and

means responsive to the current in the circuit including the armaturesof the ruin orator and the motor "For regulating theratc cl) which saidswitches r :pond to movements of the master controller to incr e suchcurrent. while at all times allow.ng

such response to decrease sucl'i ci "ii.

32. in combination, a ;1(Ti?.i"{-li()i, a motor supplied thereby, anelectrically operated ilcrrections in Letters Patea controller forvarying the electromotive force of said generator, a master switch forcontrolling the operation of said electrically operated controller, andmeans responsive to the current in the armature circuitof said motor forregulating the rate at which said electrically operated controller isoperated in response to movements of the. master switch to increasesuch. current,'wliile allowing said electrically operated controller torespond freely to movements of the master switch to decrease suchcurrent.

33. In combination, a generator, :1 motor connected thereto, a pluralityof electrically operated switches for controlling the electromotiveforce of said generator, a master switch for controlling the operationof said switches, and means responsive to the current in the armaturecircuit of the motor for regulating the rate at. which the electricallyoperated switches respond to move HICfltS of the master switch toincrease such current, while allowing said switches freely to respond tomovements oi the master switch to decrease such current.

In combination, a generator, a motor connected thereto, a power-operatedcontroller for controlling the electromotive force of said generator, amaster controller [scan] it is hereby certified that in Letters PatentNo.

for controlling the operation of said poweroperated controller, andmeans responsive to the current in the armature of said motor forstopping the current-increasing progression of the power-operatedcontroller in response to movements of the master controller when thecurrent in said circuit reaches a predetermined value, while at alltimes allowing the currentdecreasing progression of said power-operatedcontroller.

35. In combination, a generator, a motor connected thereto, a pluralityof power-operated switches for controlling the electromotive force ofsaid generator, a master controller for controlling the operation ofsaid switches, and means responsive to the currentin the armaturecircuit of said motor for stopping the current-increasing progres sionof said switches in response to movements of the master controller whenthe cur rent in said circuit exceeds a. predetermined value. while atall times allowing the cur- ,l'tlltflt('1'(2!Sl11Q' progression of saidswitches.

Milwaukee, ll'ist. June 29, I905).

in testiniony whereof l ailix my signature, in the presence of twowitnesses.

GEORGE B. SCHLEY. Witnesses CnAs. L. BYRON, Ron. E. SroLL.

989,063,'granted April ll, 1911,

upon the application of George B. Sch'ley, of Milwaukee, Wisconsin, foran improvement in Systems of Motor Control, errors appear in the printedspecification requiring correction as follows: Page 5, line 30, thereference-numeral *7 7 should read 71, and page '7, line 78, after theword cutting, the word out should be inserted; and that the said LettersPatent should be read with these corrections therein that the same mayconform to the record of the case in the Patent Oflice.

Signed and sealed this 6th day of June, A. 1)., 1911.

c. c. BILLINGS,

J Ac/mg (fina /newcomer 0/ 1 clients.

